JP2725521B2 - Thermal recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material which is excellent in water resistance and printability, and has excellent running properties during recording.

[0002]

2. Description of the Related Art A thermosensitive recording medium which uses a color reaction between a colorless or pale-colored basic dye and an organic or inorganic colorant to bring both color-forming substances into contact with heat to obtain a color image is often used. Are known. Such a thermosensitive recording medium is relatively inexpensive, and its recording equipment is compact and its maintenance is relatively easy. Therefore, it is used not only as a recording medium for facsimile machines and various computers, but also in a wide range of fields.

[0003] As one of the fields of use, a recording medium for a handy terminal has been receiving attention. Such a handy terminal is often used outdoors, and there is a problem that the recording surface gets wet and peels off in rainy weather or the like. In addition, for use in handy terminals and the like, in order to perform offset printing on a recording surface, there is an increasing demand for a thermosensitive recording medium having excellent printability.

Conventionally, for the purpose of improving the water resistance of a heat-sensitive recording layer, for example, JP-A-1-150577 discloses a combination of acetoacetyl group-modified polyvinyl alcohol and zirconyl ammonium carbonate in a recording layer. The gazette describes the use of polyvinyl alcohol and zirconyl ammonium carbonate in combination, but at present, a recording layer having sufficient water resistance and excellent printability has not yet been obtained.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a heat-sensitive recording medium provided with a recording layer containing a colorless or light-colored basic dye and a coloring agent. The present invention also provides an excellent heat-sensitive recording medium.

[0006]

Means for Solving the Problems The present inventors have proposed a heat-sensitive recording medium having a recording layer containing a colorless or light-colored basic dye and a coloring agent. For polyvinyl alcohol,
It has been found that by containing zirconyl ammonium carbonate in an amount of 1 to 30% by weight, a heat-sensitive recording material having excellent water resistance and printability and excellent running properties during recording can be obtained, and the present invention has been completed.

[0007]

The present invention is characterized in that silicon-modified polyvinyl alcohol is contained as a binder for the heat-sensitive recording layer and zirconyl ammonium carbonate as a water-proofing agent is contained in an amount of 1 to 30% by weight based on the silicon-modified polyvinyl alcohol. If the content of zirconyl ammonium carbonate is less than 1% by weight, sufficient water resistance cannot be obtained, and
If the content exceeds 0% by weight, the recording density decreases. Therefore, it is preferable to use the compound in the range of 3 to 20% by weight.

In the present invention, the silicon-modified polyvinyl alcohol acts specifically with zirconyl ammonium carbonate as compared with general polyvinyl alcohol having a saponification degree of 80 to 100 or other modified polyvinyl alcohols, thereby improving the water resistance of the recording layer. Ri <br/> Ah in which an excellent effect in printability, and the amount of such silicon-modified polyvinyl alcohol
For example, a range of 5 to 35% by weight based on the total solid content of the recording layer.
Used in enclosures. In the recording layer, besides silicon-modified polyvinyl alcohol, a binder such as starch such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, etherified starch, methylcellulose, etc. , Cellulose derivatives such as ethyl cellulose, carboxymethyl cellulose, methoxycellulose, hydroxyethyl cellulose, completely (or incompletely) saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl alcohols such as acetoacetyl group-modified polyvinyl alcohol, sodium polyacrylate, polyacrylamide , Polyvinylpyrrolidone, acrylamide / acrylate copolymer,
Water-soluble polymers such as acrylic acid amide / acrylic acid ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkaline salt, isobutylene / maleic anhydride copolymer alkaline salt, sodium alginate, gelatin, casein, etc .; poly Vinyl acetate, polyurethane, polyacrylic acid, polyacrylate, polybutyl methacrylate, styrene / butadiene copolymer, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer Latex such as coalescence can be used in combination.

In the present invention, various types of colorless or light-colored basic dyes constituting the heat-sensitive recording layer are known, and examples thereof include the following. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, , 3-Bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3 -Screw (2
-Phenylindol-3-yl) -6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-
Triarylmethane dyes such as (1-methylpyrrol-3-yl) -6-dimethylaminophthalide; 4,4'-
Bis-dimethylaminobenzhydryl benzyl ether, N-halophenyl-leuco auramine, N-2,
Diphenylmethane dyes such as 4,5-trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran,
3-ethyl-spiro-dinaphthopyran, 3-phenyl-
Spiro dyes such as spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho- (6'-methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran, rhodamine-B anilinolactam, rhodamine ( lactam dyes such as p-nitroanilino) lactam and rhodamine (o-chloroanilino) lactam, 3-dimethylamino-7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran, 3
-Diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluoran, 3- (N- Ethyl-p-toluidino) -7-methylfluoran, 3-diethylamino-7- (N-acetyl-N-methylamino) fluoran, 3-diethylamino-7-N-methylaminofluoran, 3-diethylamino-7- Dibenzylaminofluoran, 3-diethylamino-7- (N-
Methyl-N-benzylamino) fluoran, 3-diethylamino-7- (N-chloroethyl-N-methylamino) fluoran, 3-diethylamino-7-diethylaminofluoran, 3- (N-ethyl-p-toluidino)
-6-methyl-7-phenylaminofluoran, 3-
(N-cyclopentyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-p-
Toluidino) -6-methyl-7- (p-toluidino) fluoran, 3-diethylamino-6-methyl-7-phenylaminofluoran, 3-di (n-butyl) amino-
6-methyl-7-phenylaminofluoran, 3-di (n-pentyl) amino-6-methyl-7-phenylaminofluoran, 3-diethylamino-7- (2-carbomethoxy-phenylamino) fluoran, 3 − (N−
Ethyl-N-isoamylamino) -6-methyl-7-phenylaminofluoran, 3- (N-cyclohexyl-
N-methylamino) -6-methyl-7-phenylaminofluoran, 3-pyrrolidino-6-methyl-7-phenylaminofluoran, 3-piperidino-6-methyl-7
-Phenylaminofluoran, 3-diethylamino-6
-Methyl-7-xylidinofluoran, 3-diethylamino-7- (o-chlorophenylamino) fluoran,
3-dibutylamino-7- (o-chlorophenylamino) fluoran, 3-pyrrolidino-6-methyl-7-p
-Butylphenylaminofluoran, 3- (N-methyl-N-tetrahydrofurfurylamino) -6-methyl-
Fluoran dyes such as 7-anilinofluoran and 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran;

Various compounds are also known as acidic substances used in combination with a basic dye, and examples thereof include the following. Activated clay, acid clay, attapulgite, bentonite, colloidal silica, inorganic acidic substances such as aluminum silicate, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 4-hydroxyacetophenone, 4-tert-butylphenol, hydroquinone,
-Tert-octylcatechol, 4,4'-isopropylidenediphenol (bisphenol A), 4,4'-cyclohexylidenediphenol, 2,2'-dihydroxydiphenol, 2,2'-methylenebis (4-methyl- 6-tert-butylphenol), 4,4'-isopropylidenebis (2-tert-butylphenol), 4,
4'-sec-butylidene diphenol, 4-phenylphenol, 2,2'-methylenebis (4-chlorophenol), 4,4'-dihydroxydiphenylsulfone,
2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone, 4-hydroxy-4'-methoxydiphenylsulfone, 4-hydroxy-4'-iso Phenolic compounds such as propoxydiphenyl sulfone, benzyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, hydroquinone monobenzyl ether, novolak phenolic resin, phenolic polymer, benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid Acid, terephthalic acid, 3-sec-butyl-
4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid,
3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3- (α-methylbenzyl) salicylic acid, 3-chloro-5- (α-methylbenzyl) salicylic acid, 3,5-
Di-tert-butylsalicylic acid, 3-phenyl-5-
(Α, α-dimethylbenzyl) salicylic acid, aromatic carboxylic acids such as 3,5-di-α-methylbenzylsalicylic acid, and these phenolic compounds, aromatic carboxylic acids and zinc, magnesium, aluminum, calcium,
Organic acidic substances of salts with polyvalent metals such as titanium, manganese, tin and nickel.

[0011] In the present invention, which should be appropriately selected according to the basic dye and color acceptor type use ratio is used of the basic dye and color acceptor in the recording layer is not particularly limited, one Generally, a color former is used in an amount of 1 to 7 parts by weight, preferably about 1 to 4 parts by weight, based on 1 part by weight of the basic dye. The preparation of a coating solution containing these substances is generally performed by using water as a dispersion medium, stirring a ball mill, an attritor, a sand mill, or the like, or dispersing the basic dye and the colorant together or separately by a pulverizer. It is prepared as a coating solution.

Various auxiliaries can be added to the coating solution, if necessary. For example, dispersants such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, and fatty acid metal salts. Waxes such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc.
An antifoaming agent, a fluorescent dye, a coloring dye and the like are appropriately added.

Various kinds of pigments can also be used in the coating liquid, for example, kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, titanium oxide, diatomaceous earth,
Inorganic pigments such as finely divided anhydrous silica and activated clay, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, raw starch particles
And the like .

Further, a sensitizer can be used in combination depending on the purpose. Specific examples of the sensitizer include, for example, stearic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebistearic acid amide, behenic acid amide, methylenebisstearic acid Amide, N-
Methylol stearamide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate,
Benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoate, 2-naphthyl benzyl ether, m-terphenyl, dibenzyl oxalate, di-p-methylbenzyl oxalate, di-p-oxalate Chlorobenzyl, p-benzylbiphenyl, tolylbiphenyl ether, di (p-methoxyphenoxyethyl) ether, 1,2-di (3-methylphenoxy) ethane,
1,2-di (4-methylphenoxy) ethane, 1,2-
Di (4-methoxyphenoxy) ethane, 1,2-di (4
-Chlorophenoxy) ethane, 1,2-diphenoxyethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p
-Acetotoluidide, p-acetophenethidide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane and the like. Is done. The use amount of these sensitizers is not particularly limited, but it is generally desirable to adjust the sensitizer within a range of about 4 parts by weight or less based on 1 part by weight of the color former.

[0015] In order to further improve the preservability of the recorded image according to the purpose as long as the effect is not impaired, a preservability improving agent can be used in combination. Specific examples of such a preservability improver include, for example, 2,2'-methylenebis (4-methyl-6
-Tert-butylphenol), 2,2'-ethylenebis (4-methyl-6-tert-butylphenol) 2,2 '
-Methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4,6-di-tert-
Butylphenol), 2,2'-ethylidenebis (4,
6-di-tert-butylphenol), 2,2'-ethylidenebis (4-methyl-6-tert-butylphenol), 2,2'-ethylidenebis (4-ethyl-6-te
rt-butylphenol), 2,2 '-(2,2-propylidene) bis (4,6-di-tert-butylphenol), 2,2'-methylenebis (4-methoxy-6-te
rt-butylphenol), 2,2'-methylenebis (6
-Tert-butylphenol), 4,4'-thiobis (3
-Methyl-6-tert-butylphenol), 4,4'-
Thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (5-methyl-6-tert-butylphenol), 4,4'-thiobis (2-chloro-
6-tert-butylphenol), 4,4'-thiobis (2-methoxy-6-tert-butylphenol), 4,
4′-thiobis (2-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-m-cresol), 1- [α-methyl-α- (4′-
Hydroxyphenyl) ethyl] -4- [α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene,
1,1,3-tris (2-methyl-4-hydroxy-5
-Cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy -3,3 ', 5
5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyldiphenylsulfone, 2,2-bis (4-hydroxy-3,5
-Dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,
Hindered phenol compounds such as 2-bis (4-hydroxy-3,5-dimethylphenyl) propane;
N'-di-2-naphthyl-p-phenylenediamine,
Sodium 2,2'-methylenebis (4,6-di-tert-butylphenyl) phosphate and the like.

The method for forming the recording layer is not particularly limited. For example, an appropriate coating method such as air knife coating, variver blade coating, pure blade coating, rod blade coating, short dowel coating, curtain coating, die coating, etc. To form a coating liquid for a recording layer on a support, followed by drying. The support is appropriately selected from paper, plastic film, synthetic paper, nonwoven fabric and the like. The coating amount of the coating liquid for the recording layer is 1 to 10 g / m ² by dry weight, is preferably adjusted in the range of 2 to 6 g / m ^2.

[0017]

[Example 2]

Instead of 150 parts of a 10% aqueous solution of silicon- modified polyvinyl alcohol, 10 parts of acetoacetyl group-modified polyvinyl alcohol [trade name: Z-210, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. ]
Thermosensitive recording paper was obtained in the same manner as in Example 1, except that 50 parts of a 50% aqueous solution and 100 parts of a 10% aqueous solution of silicon- modified polyvinyl alcohol were used. In the preparation of the recording layer coating solution in Comparative Example 1 Example 1, silicon strange
Completely saponified polyvinyl alcohol [trade name instead of a 10% aqueous solution of 150 parts of sexual polyvinyl alcohol: PVA-
117, manufactured by Kuraray Co., Ltd.], and a thermosensitive recording paper was obtained in the same manner as in Example 1 except that 150 parts of a 10% aqueous solution was used. Comparative Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1, except that 15 parts of a 10% aqueous solution of zirconyl ammonium carbonate was not used in the preparation of the coating solution for the recording layer in Example 1. In the preparation of the recording layer coating solution in Comparative Example 3 Example 1, silicon strange
Sex polyvinyl acetoacetyl group-modified polyvinyl alcohol in place of 10% aqueous solution of 150 parts of alcohol [trade name: Z-210, The Nippon Synthetic Chemical Industry Co., Ltd.], except for using a 10% aqueous solution of 150 parts of the same manner as in Example 1 Thus, a thermosensitive recording paper was obtained.

The following evaluation tests were carried out on the five types of heat-sensitive recording papers thus obtained, and the results are shown in Table 1. Recording density Using a thermal recording simulator (TH-PDM, manufactured by Okura Electric Co., Ltd.), recording was performed at an applied head energy of 0.2 mJ / dot, and the density of the obtained recorded image was measured by a Macbeth densitometer (RD914, manufactured by Macbeth). Measured. Printability 0.4cc of ink for Offline (tack value: 13)
Printing was performed using an RI-type printing tester manufactured by Mei Seisakusho, and after passing through a water roll, printing was performed using a roll with ink, and the peeling state of the recording layer was visually evaluated. [Evaluation Criteria] ・ ・ ・: No peeling of the recording layer was observed.

・: The recording layer is slightly peeled. Δ: The recording layer is slightly peeled off. ×: Very large peeling of the recording layer. Water resistance After a drop of water was dropped on the recording surface, the recording surface was rubbed 10 times with a finger to visually determine the degree of peeling of the recording surface.

.Largecircle .: The recording surface is hardly peeled off. Δ: The recording surface slightly peeled off. ×: The recording surface peeled off a lot. Runnability The runnability was evaluated by the loudness of sound (sticking sound) generated when recording on the thermal recording paper by the above method.

◎: Very good running property.・ ・ ・: Good runnability. ×: Poor running performance

[0022]

[Table 1]

[0023]

As is clear from the results shown in Table 1, the heat-sensitive recording material of the present invention was excellent in water resistance, printability, and running property during recording.

Claims (1)

(57) [Claims] 1. A heat-sensitive recording medium having a recording layer containing a colorless or light-colored basic dye and a color former on a support, wherein a silicon-modified polyvinyl alcohol and a silicon-modified polyvinyl alcohol are contained in the recording layer. And 1 to 30% by weight of zirconyl ammonium carbonate.